So I decided to get a pet rat. I read up on everything I was supposed to and did what I was supposed to. This morning I left for work and my little guy seemed ok he was a little sleepy but he always is in the morning. When I got home he was laying in the bottom of his cage barely breathing and basically lifeless. I tried so hard to get him back as he was still trying to take breaths and his heart was still going. Unfortunately I lost him. Yesterday he was all fun and go lucky like he usually is and this death happened very fast. Can someone please help me understand what happened and what I could possibly do different next time? I am very shocked as to how this happened so fast. TiA.